A work machine (for example, an electronic component mounting device) used in Factory Automation (FA) field includes a servomotor or the like as a driving source for operating a movable section, such as amounting head. In addition, a serial encoder or the like is used to detect a rotational position necessary for controlling the servomotor. As a communication system for transmitting output of the serial encoder used in such work machine or the like, there is a communication system in which output of multiple serial encoders are collectively transmitted through one data line to save wiring (for example, PTL 1).
Network communication technology represented by the Internet has also been utilized in the FA field and, for example, there is what is called an industrial Ethernet using Ethernet (registered trademark) technology as an industrial network for the FA field. In such industrial network, it is possible to save wiring by multiplexing analog or digital information into one transmission line.